The pipe assemblies, for example the sewers of buildings, are typically renovated by changing the pipes entirely to new ones or lining the inner surfaces of the existing pipes using some suitable lining technique and material.
When changing the pipes of the building to entirely new ones, some structures of the building may need to be destroyed, e.g. by chiseling, in order to remove the old pipes from the walls of the building. Destroying and rebuilding the wall structures is expensive, dirty and time consuming work. Because of the noise and dust caused by the renovation work, it is often impossible to live in the building during the renovation.
Pipe systems may also be renovated by coating their inner surfaces. One such technique is so called lining technique where a liner sleeve is slid into the sewer being repaired and impregnated using some suitable material, e.g. epoxy resin, upon hardening of which a continuous and tight pipe is formed. The lining is stiff, acid proof and environment friendly, among others. The thickness of the wall of the sleeve is 2-4 mm, depending on the diameter of the pipe, and its smooth inner surface guarantees excellent flow properties. The durability, environmental safety and life of the installed and hardened pipe are comparable to the respective properties of new pipes.
One problem with the lining technique is, that when the sleeve has been installed e.g. into a thick vertical main line of a pipe system, all joints leading e.g. to thinner pipes coming from the apartments of a residential building are blocked. Holes must thus be drilled to the joints in order to allow waste water to flow from the pipes coming from the apartments to the main line. In prior art solutions, these holes are drilled from the main line using e.g. a robot bore. The robot bores are large, expensive and complex devices whose operation requires special skills from their user. As a result of erroneous operation, the hole may be drilled partially or entirely into wrong location or at least the finish may remain rough. Such quality is typically not acceptable, because waste may stick onto the rough areas of the sewer pipe and accumulate over time into thicker layer and eventually even block the sewer. Neither is it acceptable, that standing water remains in the rough spots of the joint area. Another problem with the robot bores is their unsuitability for use in main lines having bends in them. Because of its size, it may not be possible to move the robot bore in the main line to the position where the hole should be bored.
Because of the problems related to the lining techniques, their popularity in the pipe system renovation projects has remained rather small. By solving these problems, the efficiency of pipe renovation may be significantly improved and thus the cost of renovation may be lowered.
The object of the present invention is to disclose a device and method for machining pipe assemblies, e.g. sewer pipes of a residential building, and especially their joint areas.
An aspect of the present invention is a machining device for machining the material of e.g. a pipe system comprising a joint area between a pipe having a smaller inner diameter and a pipe having a larger inner diameter. The device is characterized in that it comprises protruding parts, that have been adapted to position the device or at least a part of it inside the pipe of the pipe system having the smaller diameter, steerable and e.g. actuator operable means for removing material from the joint area of the pipe system and steering device for controlling the direction of the machining device in relation to the longitudinal axis of the pipe having thinner diameter in the pipe system while removing material from the joint area of the pipe system.
The machining device may comprise a rotatable spindle which may be coupled for example to an external actuator. In an embodiment, the protruding parts positioning the device may be attached to this rotatable spindle.
The material to be removed may be e.g. the construction material of the pipe or suitable lining material, e.g. a polyester sleeve impregnated with epoxy resin, that has been attached to the inner surface of the pipe.
The pipe system advantageously comprises a thinner and a thicker pipe. “Thinner” and “thicker” refer herein to the inner diameters of the pipes. The device according to an embodiment of the invention may be adapted to machine the material of a joint area of the pipe system from inside of the thinner pipe of the assembly. The thinner pipe of the pipe system may be joined with the thicker pipe in any angle, typically however in the angle of 30-60 degrees, most advantageously in the angle of 45 degrees.
The machining device may be adapted to be operated from the thinner pipe of the pipe system being machined.
The machining device may be adapted to be steered in at least one direction from the thicker pipe of the pipe system being machined.
The protruding parts to be attached to the spindle of the machining device may be adapted to be attached to the spindle in a radial manner.
The positioning of the machining device may mean e.g. centering of the spindle inside the thinner pipe of the pipe system.
The means for removing material may be adapted to remove material from the pipe system for example by sanding, honing or cutting. In a preferred embodiment the motion causing the honing or cutting is a rotating motion. The means for removing material may be adapted to puncture from inside of the thinner pipe a hole to the lining installed into the thicker pipe of the pipe system and/or to hone the edges of the punctured hole.
The means for removing material may be adapted to be steerable for example by positioning the removing means or its part to a desired position inside the pipe, e.g. to the center of the pipe, by deviating the rotational axis of the removing means or directing the rotational axis of the removing means to a desired direction.
The protruding part may advantageously be adapted to lean to the pipe of the pipe system in a flexible manner, for example using elastic or pneumatic force. The protruding part, which may be adapted to be attached to the rotatable spindle of the machining device, may comprise e.g. brushes, a rough sanding surface or other suitable, e.g. grinding or chipping means for removing material from the pipe system, e.g. from its joint area, e.g. from the edges of a hole made to the joint area.
The protruding part may also comprise one or multiple lamellae that, when bent, cause an elastic force. The lamellae may comprise for example abrasive band. Some reinforcement member made of e.g. rubber or other suitable material may be attached to the abrasive band e.g. by moulding or laminating to effect the elastic force and/or to improve the strength of the abrasive band.
The machining device may also comprise a steering device for controlling the longitudinal (rotational) axis of the spindle of the machining device in relation to the longitudinal axis of a pipe of the pipe system, for example by deviating the machining device from the direction of the longitudinal axis of the pipe or keeping the machining device in a certain direction, e.g. in the direction of the longitudinal axis of a pipe. The steering device may be mounted on a bearing so that the rotating movement of e.g. the spindle of the machining device does not transmit to the steering device. The steering device may comprise some suitable deviating device, e.g. a bendable wire, rope or cable. In an embodiment, a weight element may be attached to the rope or cable. In some embodiments, the deviating device may also be some suitable rigid structure, e.g. a rod.
The machining device may also comprise e.g. detachable means for puncturing a hole to the joint area of the pipe system. Such means may comprise e.g. a surface that sands or chips material from the location of the hole to be made. The surface may be e.g. a plate or a suitably formed curved surface. The surface may comprise a roughening made of hard metal pieces or some other suitable material. In an embodiment of the invention, the grinding or chipping function may be achieved with a suitably selected form of the surface, e.g. with sharp edges.
The machining device may advantageously also comprise a bendable torque transmitting member, e.g. a cable, that has been attached to the spindle of the machining device and that may rotate the spindle using an actuator. The torque transmitting member may thus be adapted to be attached to a torque producing actuating device. This member or some other suitable members attachable to the device may advantageously be used for moving (pushing and pulling) the machining device inside the thinner pipe of the pipe system.
A second aspect of the present invention may be a machining device for machining material of e.g. a joint area of a pipe system comprising a thicker and a thinner pipe. The machining device is characterized in that it comprises bendable abrasive bands attachable to the rotatable spindle of the machining device. The abrasive bands are adapted to position and/or direct the machining device inside the pipe of the pipe system and to sand the inner surfaces of the pipe. In addition to the abrasive bands, a blade may be adapted to be attached to the rotatable spindle for the purpose of removing material from the pipe system, e.g. from the joint area of the thinner and thicker pipe.
A third aspect of the invention is a method for machining the joint area of a pipe system comprising a thinner and a thicker pipe. In the method, a machining device according to e.g. an embodiment of the first or second aspect of the invention may be used.
The method may thus be characterized in that in the method a hole is punctured from inside of the thinner pipe to the thicker pipe in the joint area of the pipe system and the edges of the punctured hole are ground (sanded), e.g. to the same level with the inner surface of the thinner pipe, using a rotatable steerable sanding device, the direction of the rotational axis of which may be controlled while sanding the edges of the punctured hole.
The punctured hole may, before the sanding, may have a diameter that is e.g. at least 1%, 5% or 10% smaller than the inner diameter of the thinner pipe of the pipe system. The hole may be punctured e.g. using a self-positioning or steerable puncturing device, e.g. a bore attached to centering means. While sanding the edges of the hole, the rotational (longitudinal) axis of the sanding device may be controlled, e.g. deviated from the direction of the longitudinal axis of the thinner pipe using a steering device or the sanding device may be kept in a certain direction using the steering device, e.g. in the direction of the thinner pipe. Advantageously, the sanding of the hole may be performed from the thinner pipe of the pipe system. While sanding the edges of the punctured hole, the device may be steered e.g. from the thicker pipe of the pipe system.
In the following detailed description, a preferred embodiment of the device and the method is described.